The Hannah Montana star turned 19 on Nov. 23, and celebrated with a birthday party thrown by pal Kelly Osbourne at Beacher's Madhouse at the Hollywood Roosevelt Hotel.

In a video of the private bash obtained by The Daily, Cyrus seemingly admits to being a fan of smoking marijuana.

"This is amazing," she says of a cake baked to look like known pot-smoker Bob Marley, which Osbourne presented to her friend. "You know you're a stoner when your friends make you a 'Bob Miley' cake. You know you smoke way too much f––ing weed."

While celebrating her 18th birthday last year, Cyrus was seen smoking salvia, a legal herb with hallucinogenic effects, from a bong at a party.

"It was a bad decision," she said of the incident, which was caught on camera, "because of my fans and because of what I stand for."

A rep for Cyrus responded Monday to the latest incident, saying, "This is so ridiculous. The cake was a joke, and Miley was being sarcastic."

And Osbourne Tweeted about it – concurring it was a joke: "let me make something very clear after @MileyCyrus salvia incident we started calling her bob miley as a JOKE!" she wrote. "the cake was also A JOKE! it makes me sick that @MileyCyrus so called 'friends' would sell her out and lead people 2 believe she is someone that she is not!"

Osbourne continued in another Tweet hash-tagged #think: "u guys if @MileyCyrus is not recording/filming/touring she is works everyday how could she possible do all that if she was a stoner!"